This invention concerns a connecting rod for a piston engine and in particular for a twin crankshaft piston engine.
In piston engines that have a long stroke-to-bore ratio, the connecting rods must be long and narrow so that they do not collide with the lower peripheral edge of the cylinder. Such long and narrow connecting rods, however, are more likely to buckle than wider connecting rods.
Particularly when connecting rods are intended for use in twin crankshaft piston engines where both crankshafts are laterally offset to one another in relation to a center-line of the cylinder, the connecting rods enter the cylinder from the side at a flatter angle than is the case with piston engines with only one crankshaft, so that out of principle there is a higher risk that they will collide with the lower cylinder edge. Connecting rods therefore need to be even narrower for twin crankshaft piston engines. There have been considerations in the prior art to manufacture curved connecting rods for twin crankshaft piston engines. Such a curved connection rod is, for example, known from DE-AS 1 775 160. Curved connecting rods of this kind, however, are questionable from a statistical point of view, particularly with regard to high-performance piston engines.
FR-A 1 596 918, for instance, establishes a connecting rod with a narrow shank section at the piston end and a wider shank section at the crankshaft end, wherein the shank sections are bordered by surrounding ribs that run in the direction of the axes of the eyes of the connecting rod. These surrounding stakes, however, cover almost the entire thickness of the connecting rod and increase the risk of the lateral edges of the ribs of the connecting rod coming into contact with the circular lower peripheral edge of the cylinder.